Magazine screw-plug fuse



March 10. 1925.

J. SACHS MAGAZINE SCREW PLUG FUSE Filed Feb. 26, 1923 2 Sheets-Sheet 1 March 10, 1925.

J. SACHS MAGAZINE SCREW PLUG FUSE Patented Mar. 10, 1925.

UNITED STATES JOSEPH SACHS, OF HARTFORD, CONNECTICUT.

MAGAZINE SCREW-PLUG FUSE.

Application filed February 26, 1923. Serial No. 621,257.

To all whom it may concern:

Be it known that I, JOSEPH SACHS, a citizen of the United States, residing at Hart-ford, in the county of Hartford and State of Connecticut, have invented a new and useful Improvement in Magazine Screwlug Fuses, of which the following is a specification.

This invention relates to those screw plug fuses which have a plurality of fusible elements so arranged that when an element is blown another elementcan be immediately substituted in the circuit which the device is designed to protect.

The object of the invention is to provide a device of this character which has a :h

magazine carrying a plurality-of fusible elements that is simple and cheap to manufacture and which is so designed that when a fuse is blown the circuit may be quickly restored by merely withdrawin the magazine from the screw shell and then putting it back in a new relation.

This object is attained by attaching to the metallic shell which is designed to screw into the common socket or base receptacle, a conducting contact, and providing amaga zine shaped to be inserted into the screw shell, which magazine carries a plurality offusible elements that have their outer ends connected to a common center contact and have their inner ends separated and each adapted to register with and be engaged with the shell contact according to the rotational relation of the magazine and the shell when the magazine is thrust into the shell. In other words when the magazine is thrust into the shell one of the fusible elements engages the shell contact and closesthe circuit through the plug. When that fuse is blown the magazine is withdrawn from the shell, turned a little and then thrust back into the shell so that another fuse engages the shell contact and completes the circuit. This can be repeated until all of the fuses carried by the magazine are blown, and then if desired the magazine may be reloaded with fusible elements.

In the accompanying drawings Figure 1 shows a central longitudinal section of one form of device that embodies the invention. Fig. 2 shows a view of one end of a five link removable magazine, with three fusible strips in operative position, two of the strp e paths being unoccupied Fig. 3 is a si View of the magazine.

Fig. 4 is a view of snugly fit 1n the screw shell.

may as shown in Fig. 1, be

the outer end of the magazine. with three fusible elements and with the center contact omitted. Fig. 5 shows a bottom view of the assembled device illustrated in Fig. 1.

ig. 6 is a longitudinal section of a modified design. Fig. 7 isa transverse section on plane indicated by the dotted line 77 on Fig. 6. Fig. 8 is a plan of the center contact of the magazine shown in Fig. 6. Fig. 9 is a side elevation, with part broken away, of a magazine with a different form of center contact. Fig. 10 is a plan of the center contact shown in Fig. 9.

The base 1 of the plug is desirably, made of porcelain and t e metallic screw shell 2 asone end molded therein. To the inner wall on one side of the screw shell is fastened a contact 3 of conducting material. This contact is illustrated as a spring finger with its outer end fastened to the shell by a rivet 4 and its inner end free to yield radially of the shell. The outer end of the nger may be fastened near the outer end of the shell as shown in Fig. 1, or further in as shown in Fig. 6.

he magazine 5 is desirably made of p celain of a maximum diameter that will In the designs of magazine illustrated there are five grooves 6, extending longitudinally in the outer wall and five passages 7 extending through the magazine from end to end and communicating with the grooves. 'The grooves may extend the entire length of the outer wall of the magazine as shown in Fig. 3, or only part way as shown in Fig. 9. The number of these strip paths may obviously be varied.

The fusible elements are of common material and capacity, those shown being in the form of metallic strips 8. These strips are thrust through the passages and the inner ends 9 are folded over the edge of the inner end of the magazine so as to lie isolated from each other in the grooves on the exterior. The outer ends 10 of the strips bent over the outer end of the magazine and be held in place by the flange 11 of a metallic cap 12 which forms the center contact of the plug.

his cap may be secured in place in an desired manner, as by screw 13. v

by a metallic cap 15 which has fingers 16 -mentmg comp ends by a screw the magazine as illustrated in Figs. 6

the magazine may that extend into the strip passa es through the magazine. This cap may e retained in place by the fingers and also by a ccof the magazine around the cap. The ends 18 of the fusible strip may be bent over on the inside of the outer end of the .cap as shown in Fig. 6. I

In this case a threaded perforation 20 may be used to hold the ends of the strip and make the necessary electrical connection with them, the spider being drawn to place so as to clamp the strip 21 which forms the outside center terminal of the plug. To isolate the passages for the strips an insulating tube 22 may be inserted into the central boreit of an The outer ends of all of the fusible elements are electrically connected with the center contact, while the inner ends of the fusible elements are isolated in the grooves in position to be engaged, one at a time, with the contact finger when the magazine is thrust into the shell. When the fusible element that electrically connects the contact finger attached to the shell with the center contact and closes the circuit through the plug, is disrupted by an excess flow of current, the magazine is pulled out of the shell, partially rotated and then pushed backv into the shell so that one of the fusible elements that remains complete will. reestablish the circuit., In the forms shown the shell contact is substantially .the shape of the grooves inthe exterior of the magazine so that it forms a guiding key when the magazine is inserted into the shell as Well as makingcontact with the'end of one of the fusible elements carried by the magazine. After all of the fusible elements have been blown be re-fused by removing the common end contact, inserting fresh strips, bending the ends of the strip and then replacing the cap or end contact. The passages in the magazine for the fusible links-may be varied in shape and number as desired, and the shape of the shell contact and the manner of connecting the contact with the shell may be changed as is apparent, without departing from the invention.

The invention claimed is 1. A fuse plug having an insulating base, a metallic screw shell with its inner end embedded in the base, a metallic spring finger having its outer end electrically attached to the outer end of the screw shell, said fin er extending into and adapted to yield radiailly ound l7 molded into the end' metallic spider 19 with a within the shell, and an' insulating block sha ed to fit within and movable longitudia ly into and out of the shell, said block carrying a plurality of fusible elements that are joined at their outer ends to a common center contact on the block and that have their inner ends adapted to be engaged one at a time by said finger.

2. A fuse plug having an insulating base, a metallic screw shell with its inner end embedded in the base, an insulating block movable longitudinally into and out of the shell, a plurality of fusible elements extending through the block, said elements having their outer ends joined to a common contact on the block and that have their inner ends bent over the inner end of the block to the outer surface of-the block, and a metallic spring finger having its outer end electrically attached to the shell and its inner end bearing radiall with a yielding pressure against the en of one of the fusible elements.

3. A fuse plug having a metallic screw shell, an insulating cylinder shaped .to fit within the shell, said cylinder having longitudinal grooves in its surface, a plurality of fusible elements that are joined at their outer ends to a common contact and that have their inner ends bent over the inner edge of the cylinder into said grooves, and a metallic spring finger having its outer end elec trically attached to the shell and its inner end extending in one of the grooves in the cylinder wall and bearing radially with a yielding pressure against the bent over end of one of the fusible elements.

4. A fuse plug having an insulating base, a conducting screw shell with its inner end embedded in the base, adapted to fit within and movable longitudinally. into and out of the shell, said block having a plurality of passages from end JOSEPH SACHS.

an insulating block Jim... 

